The present invention relates to integrated circuit (IC) device assembly and, more particularly, to lead frames for semiconductor packages.
Many current quad-flat no-leads (QFN) packages include more than one row of leads to increase the number of inputs and outputs (I/Os) of the packages while maintaining the package size. FIG. 1 is an isometric view showing a bottom surface of a conventional QFN package 100. The QFN package 100 is assembled using a lead frame 102 including first and second rows of leads 104 and 106 surrounding a flag 108. A die (not shown) is mounted on the flag 106 and electrically connected to the first and second rows of leads 104 and 106. Then the die and the lead frame 102 are encapsulated by a molding compound 110.
FIG. 2 shows a cross sectional view of the QFN package 100 after encapsulation. A die 112 is mounted on the flag 108 and electrically connected to the first and second rows of leads 104 and 106 with bond wires 114. In a conventional method, the lead frame 102 is provided having the second row of leads 106 connected to the first row of leads 104. Therefore, after the molding or encapsulation process, an additional half-cutting of the bottom side of the QFN package 100 with a blade 116 must be performed to disconnect the second row of leads 106 from the first row of leads 104. Further, selective plating on the cutting sides 118 of the first and second row of leads is also required. Accordingly, it would be advantageous to have an alternative way to assemble a QFN package having multiple rows of leads.